What Temperature is Too Hot to Water Your Grass?

sprinkler watering grass in lawn

Summer can pack quite a punch, bringing scorching heat and extended dry spells. If you’re all about keeping your lawn in pristine shape, you may wonder what temperature is too hot to water your grass.

In this article, we’re tackling that burning question to help you keep your grass green and thriving, no matter how high the mercury climbs.

Why watering your grass is important

Watering your lawn correctly is one of the main lawn care tasks to keep your grass green and healthy. Let’s explore the advantages of irrigation:

  • Maintains your lawn’s vitality: A proper water supply can visibly impact your lawn’s overall well-being. It helps with photosynthesis (how plants convert water, sunlight, and carbon dioxide into energy) and other vital processes needed for plant development.
  • Helps with root development: Regular, deep watering helps your grass develop a sturdy, robust root system, which allows it to withstand various environmental stressors, including drought, diseases, and pests.
  • Enhances visual appeal: When you water your lawn the right amount at the right time, you’re contributing to a lush, vibrant, healthy lawn your neighbors will surely notice. Well-hydrated blades of grass stand up straighter, shine better, and look healthier.
  • Boosts stress recovery: Your grass is exposed to various daily challenges, including extreme heat and heavy foot traffic. Regular irrigation can help your grass regenerate and bounce back no matter what it comes up against.
  • Prevents soil compaction: If you water your lawn just right (avoid overwatering), you can avoid compacted soil. This happens when excess water particles fill the spaces within the soil, creating a compact structure that limits the movement of air, water, and nutrients throughout the soil.
  • Supports seed germination: When it comes to new lawns, consistent watering is crucial in the first couple of weeks (the germination process varies depending on grass type). It contributes to healthy grass development and long-term health.
  • Prevents weed growth: A correct watering routine is key to growing dense, lush turf that makes it challenging for weeds to establish themselves.

When is it too hot outside to water your grass?

water coming out of a sprinkler in a lawn

In temperatures over 90 degrees Fahrenheit, it’s best to turn off your sprinklers during the day. Essentially, any water you apply to your grass evaporates into thin (hot) air without reaching the soil to support your lawn. 

The best time to water your grass is between 5 a.m. and 9 a.m. when conditions are less windy, sunlight is less intense, and evaporation is less likely. Early morning irrigation allows the water to penetrate the soil and reach the roots. It also gives the water left on the foliage time to dry, which reduces the risk of fungal lawn diseases.

If you prefer to sleep in or have limited time in the morning, another option is to water your grass in the late afternoon. However, this is risky because without the sun to dry the water on your grass blades, your lawn can become an easy target for diseases and pests overnight. To mitigate the risks, opt for using a drip irrigation system. It targets the grassroots directly without touching the foliage. 

The dangers of watering your grass in hot weather

Watering your grass when it’s not advisable carries potential threats to both the grass and the environment. Bear these risks in mind before picking up your garden hose or turning on your sprinklers in hot weather:

  • Shallow root growth: Watering your grass at the wrong time in hot weather is an easy way to damage it. Don’t irrigate between 10 a.m. and about 4 p.m., as most of the water will evaporate instantly without benefitting your lawn. It will also cause shallow root growth, weakening the grass and making it more vulnerable to drought.
  • Fungal diseases: Hot and humid weather typically fosters fungal growth. Overwatering (as one is tempted to do in scorching heat) can create excess moisture on the grass blades and soil surface, causing mildew, brown patch, and dollar spot. These diseases can damage or kill the grass, ultimately leading to thinning or bare patches in your lawn.
  • Soil compaction: The hotter it is outside, the more water you’ll be tempted to give your grass. At one point, this process will cause waterlogging and change the structure of your soil. Compaction blocks the soil’s access to nutrients, air, and water, causes drainage and erosion issues, and drastically reduces the soil’s ability to support healthy grass growth.
  • Waste of water: Last, but not least, watering during hot weather is a wasteful practice that doesn’t benefit the grass and contributes to water waste. This is of particular importance in drought-prone areas where water restrictions may apply. 

Signs of heat damage to your grass

Damaged lawn with bare spots. Patchy grass, lawn in bad condition and need maintaining

Heat damage as a result of scorching summer days can manifest in a multitude of ways. Keep an eye out for these common signs of stress:

  • Discoloration: You’ll notice a difference in color between grass exposed to direct sunlight, which may appear faded or discolored, and grass that receives shade, which will look vibrantly green. Color fading begins at the tips and progressively extends to the entire surface.
  • Wilting: Grass that is heat damaged will appear limp or wilted, losing its vitality. This is typically a sign of moisture loss.
  • Thinning: During summer, you may notice thin or bare areas in your lawn. Heat renders grass unable to fill in those areas, contributing to a patchy look to your lawn.
  • Slow growth or no growth: Under the intense summer sun, your grass may grow slower than usual, if at all. You’ll notice a reduced need to mow your lawn due to lack of growth.
  • Weeds: If your grass is struggling, it won’t be able to compete with weeds, leading to an increase in pesky plant populations.
  • Crunchy, burned texture to your grass: Dehydrated, damaged grass will develop a crunchy texture you’ll notice straight away. 
  • Fungal diseases: Stressed grass tends to succumb to various fungal diseases faster than healthy grass. These can present as moldy growth, patches in the grass, or other patterns you may not have seen before. 
  • Pest activity: As your grass grows weaker due to hot weather, pests grow feistier. Rodents and insects like grubs, army worms, and chinch bugs may find the vulnerable state of your grass particularly appealing. They’ll feed on the remaining grass blades and roots, possibly causing irreparable damage.

How to water your grass the right way

Cool-season grasses typically require 1 inch to 1.5 inches of water weekly, though during particularly hot conditions more water may be required to prevent dormancy. For proper moisture absorption and retention, watering should be done at temperatures between 60 and 75 degrees Fahrenheit. Do so three times a week in equally spaced intervals. 

Drought-resistant cool-season varieties include:

  • Tall fescue
  • Kentucky bluegrass

Warm-season grasses need less water than cool-season grasses, which is typically about ½ inch to 1 inch of water weekly. Ideal temperatures for watering range from 80 to 90 degrees Fahrenheit.

Warm-season cultivars that can withstand drought are:

  • Bermudagrass
  • Bahiagrass
  • Zoysiagrass
  • Buffalograss
  • St. Augustinegrass

Watering your grass requires the perfect balance. As temperatures soar, you may be tempted to overwater your grass to compensate for the hot weather. You also might think that frequent, brief watering sessions will do wonders for your grass, but the reality is that they will damage it in the long run.

Watering less often but for longer periods encourages the grassroots to search for moisture and grow deeper into the soil. This practice also trains your grass to access water stored in the soil and better manage drought and other stressors.

Underwatered grass will display the following symptoms:

  • Yellow, brown, or grey grass. Even though this symptom doesn’t always mean your grass isn’t sufficiently hydrated, most of the time, it’s a sign of underwatering.
  • Footprints that remain on the grass long after someone walked on it. This is due to the grass being unable to spring back up as quickly.
  • Dry, crispy texture to the grass.
  • Slow growth or no growth, which can be temporary or permanent, depending on how long the grass was deprived of water.

Overwatered grass will display the following symptoms:

  • Puddles on your lawn that persist long after you’ve finished watering your grass. When the soil isn’t absorbing water, it’s either compacted or overly saturated. As soon as you notice runoff, you should take a closer look.
  • Fungal growth in your grass – a clear sign of a damp environment and overwatering.
  • Grass that feels squishy when you step on it.
  • Slow growth or no growth, evidenced by sparse areas and bare patches on your lawn.
  • Yellow grass, as a result of oxygen deprivation (which stems from overwatering).
  • Weeds and pests in your grass. These nuisances thrive in damp conditions, and if you’re not careful, they can easily overrun your lawn.
  • Thatch buildup, as a result of shallow roots that don’t burrow deep into the soil (poor root growth is a result of overwatering). These roots decompose and stay on top of the lawn as thatch, smothering the grass and blocking its access to nutrients, air, and sunlight.

How to maintain the health of your lawn in hot weather

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Given the significant stress your lawn endures in hot weather, it’s essential to implement responsible lawn care practices throughout the summer season. Here are a few pointers to help you maintain that manicured, dreamy lawn despite the blazing temperatures:

  • Plant drought-tolerant grass varieties (mentioned above). These grasses require less water and maintenance, and they’re better able to withstand consistent hot and dry conditions.
  • Cut your grass taller. Raising your mower blade during hot weather pays off. Taller grass shades the soil and maintains moisture necessary for root growth and lawn health.
  • Mow less frequently. To minimize stress on your grass, cut back on your mowing. Remember to never cut more than one-third of the grass blade to prevent scalping and long-term damage.
  • Keep a strict fertilization schedule. Use a slow-release or organic fertilizer to help your grass withstand the stress of summer. Nutrients will be released over time and nurture your grass correctly. Opt for a fertilizer with a low nitrogen content to keep growth and water waste to a minimum.
  • Leave grass clippings. When it’s hot out, don’t bag your clippings. They’ll act as natural mulch, retaining moisture and feeding your soil with extra nutrients.
  • Incorporate shade. To protect your lawn from heat stress as much as possible, provide shade in the form of trees or shrubs nearby. Limiting direct sunlight can significantly contribute to the health of your lawn.

FAQ about what temperature is too hot to water your grass

What can I do to fix my underwatered lawn?

If you’ve neglected your lawn as of late, you’ll be happy to know that all is not lost. Follow these tips to bring your lawn back to life:

  • Put together a proper lawn watering schedule, and deep water your lawn for three or four consecutive days. Water it until it’s soaked and can’t absorb any more liquid to encourage root revival and strengthening.
  • Spread a thin layer of mulch across your lawn to retain moisture, reduce water evaporation, and help the soil underneath regulate its temperature. Some excellent organic mulch options include grass clippings, leaves, bark, wood chips, hay, and straw.
  • Depending on your soil type and condition, you may need to add organic fertilizer to improve soil structure and its ability to absorb and retain moisture.
  • Don’t mow your lawn too short (also called scalping) to allow your soil some shade for moisture retention.

What can I do to fix my overwatered lawn?

We get it: drenching your lawn on a scorching hot day can seem like a good idea. But give your lawn more water than it needs, and you’re setting it up for failure. Fortunately, your overwatered lawn can recover if you make proper long-term adjustments. Take a shot at these strategies for restoring your lawn to its former glory:

  • Reduce the frequency of your waterings, soak the soil when you irrigate, and allow the soil to dry between sessions to help the root system recover. Also, watch the weather closely to avoid combining irrigation with rainfall and choking your grass.
  • Make sure your soil is well-draining to prevent waterlogged conditions in the future. Refer to our section above on soil types.
  • Cut your grass according to its recommended height. Mowing taller will help the grass better protect the soil and retain necessary moisture.
  • Overwatering causes compacted soil, which can be relieved with core or spike aeration. This helps air, water, and nutrients correctly enter and circulate through the soil.

What else can I do to keep my lawn healthy in hot weather?

In the peak of summer, you’ll want to follow a few tips and tricks to keep your lawn healthy and vibrant.

  • Don’t scalp your grass. Never cut more than one-third of the grass height at one time. With more surface available, your grass will hold onto moisture better.
  • Avoid mowing your grass in drought conditions. Instead, take a break and return to your regular schedule after irrigation or rainfall. Once the grass is dry, you can cut it.
  • Keep your lawn mower blades sharp. Cutting with dull blades will tear your grass, increasing its vulnerability to diseases and pests. It will also change to an unattractive brown color, negatively affecting your curb appeal.
  • Don’t bag your grass clippings. When it’s hot out, it’s best to leave them on your lawn as mulch. They’ll act as a natural fertilizer and ensure moisture for your grass. A mulching mower can make the process easier, though any mower will do.

What are some drought-friendly landscaping ideas?

xeriscape landscaping with small bushes
Tom Hilton | Flickr | CC BY 2.0

If you’re actively seeking drought-friendly ways to keep your yard fresh, why not give these ideas a try:

  • Try xeriscaping
  • Reduce the size of your lawn
  • Grow native plants 
  • Group vegetation with similar watering needs

How does my soil type factor into lawn watering?

As you devise a watering plan, consider your soil type: clay, sandy, silty, or loamy. Each retains and drains water differently, affecting the condition of your lawn in hot weather.

Clay soils are known to hold water well – almost too well. Typically, this aspect contributes to pooling, runoff, root rot, and fungal diseases. However, when it’s blazing hot, and the water seems to disappear in the blink of an eye, this soil type’s ability to hold onto moisture becomes useful. It also means clay soil won’t require as much water as sandy soil. 

Water your clay soil for about 15 minutes each time until the desired amount, 1 to 1.5 inches, is reached.

Sandy soils are the polar opposite of clay soils in that they absorb water well but drain quickly, which can be a disadvantage in hot weather. Give soil high in sand ⅓ inch of water three times a week and allow the water to reach deep into the soil. If needed, increase the frequency, but always water the soil deep to maintain its health.

Silty soils are prone to erosion, so do your best not to overwater (which may be tempting if the weather is too hot). They drain better than clay soils but less quickly than sandy soils, so you can count on a relatively stable water supply for your grass.

Water silty soils twice a week with ½ inch of water each time and adapt to the weather conditions in your area. 

Loamy soil combines sand’s drainage qualities and clay’s water retention qualities, providing the proper balance for your grass. Lawns with loamy soil need about ½ inch of water twice a week to stay resilient throughout the hot months.

If you don’t know your soil type, you can test your soil and send the samples to your local Extension Office for identification and amendment suggestions.

Pro tip: To determine your soil’s moisture levels, press the tip of a screwdriver into your soil. It should easily penetrate the surface to a depth of 6 to 8 inches. If it doesn’t, the soil is dry, and it’s time to adjust your watering schedule accordingly.

Professional help when you need it

Let’s face it, not everyone has a green thumb. If tending to your lawn isn’t your strong suit, getting help from a local pro can be an excellent alternative. They’ll handle the workload and keep your outdoor space looking lush, vibrant, and stunning year-round. 

Whether it’s mowing, fertilizing, or pest management, these professionals are equipped to handle any task effortlessly. So why not spend your time doing activities you love, knowing that your lawn is receiving top-notch care?

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Andie Ioó

In my free time, I enjoy traveling with my husband, sports, trying out new recipes, reading, and watching reruns of '90s TV shows. As a way to relax and decompress, I enjoy landscaping around my little yard and DIY home projects.